Point-of-Care Diagnostics
Group leader Saara Wittfooth, PhD (on maternity leave); Noora Ristiniemi, MSc
Personnel
Senior scientist Lasse Välimaa, PhD
Special laboratory assistant Pirjo Laaksonen
Project researchers Etvi Juntunen, MSc; Heidi Hyytiä, MSc; Marja-Leena Järvenpää, MSc; Tanja Savukoski, MSc; Teppo Salminen, MSc; Tiina Myyryläinen, MSc
Professor Kim Pettersson, PhD
Research
The overall objective of the Point-of-care (POC) research group is to develop assays - mainly immunoassays and chemical assays - for use in near-patient diagnostics or other decentralized conditions such as food or environmental diagnostics. Such assays must provide rapid, sensitive and reproducible results directly from samples (immunoassays from whole-blood) or after simple pre-treatment of samples. Furthermore, the assay concepts should be readily transferable to small and simple platforms requiring minimal technical skills from the end user.
Our research focuses on two main areas: on novel markers for detection of common diseases, in particular cardiovascular and infectious diseases, and on development of assay technology. Combination of our knowledge of core analytical targets with technological expertise has already resulted in state-of-the-art assay concepts for point-of-care testing.
The triage of acute coronary syndromes (ACS) and acute myocardial infarction (AMI) has been the main clinical application in our project during the last years. Measurement of cardiac troponin I or T (cTnI or cTnT) is now a well-established clinical routine for the diagnosis of AMI, but the biochemical nature of especially cTnI complicates its measurement. Moreover, cTnI assays should be analytically very sensitive in order to enable the detection of minimal myocardial injury. The recent discovery of commonly occurring autoantibodies to troponin, which negatively affect cTnI assays, has lead to the development of immunoassays that are less affected by these autoantibodies, thus increasing the clinical sensitivity of cTnI assays especially in the early phase of AMI. In addition to cTnI, which is a marker of myocardial necrosis, our research also focuses on pregnancy-associated plasma protein-A (PAPP-A), which has been reported to be a specific marker of rupture of atherosclerotic plaques. PAPP-A may provide early detection of ACS even in the absence of myocardial necrosis, and it is also likely to provide valuable prognostic information.
Developments in the assay technology include intrinsically fluorescent reporter molecules (lanthanide chelates) and "all-in-one", dry reagent-based single assay wells or chips. Combined together, these concepts enable any sample matrix (e.g. whole blood, serum, plasma, or urine) to be used for quantitative measurement without any reagent additions in a simple one-step procedure. More recent areas of interest include alternative solid phase immobilisation techniques, such as spot-coating approaches; antibody engineering and lateral flow-based point-of-care tests. Simple and rapid methods with excellent analytical and clinical performance are crucial for decentralised testing, and efforts are going on to develop means of achieving these requirements.
The POC group consists of several independent projects. Our primary sources of funding are TEKES and the diagnostic industry. Collaborative partners are found among central laboratories of several Finnish university hospitals.
Recent publications
Lund J, Wittfooth S, Qin QP, Ilva T, Porela P, Pulkki K, Pettersson K, Voipio-Pulkki LM. (2010) Free vs Total Pregnancy-Associated Plasma Protein A (PAPP-A) as a Predictor of 1-Year Outcome in Patients Presenting with Non-ST-Elevation Acute Coronary Syndrome. Clin Chem.
Hyytiä H, Ristiniemi N, Airas L, Pettersson K, Hellman J. (2010) Development of an immunoassay for the detection of cystatin C dimers. J Immunol Methods. 355:14-20.
Ilva T, Lund J, Porela P, Mustonen H, Voipio-Pulkki LM, Eriksson S, Pettersson K, Tanner P, Pulkki K. (2010) Early markers of myocardial injury: cTnI is enough. Clin Chim Acta. 400:82-5.
Pettersson K, Eriksson S, Wittfooth S, Engström E, Nieminen M, Sinisalo J. (2009) Autoantibodies to cardiac troponin associate with higher initial concentrations and longer release of troponin I in acute coronary syndrome patients. Clin Chem. 55:938-45.
Ylikotila J, Välimaa L, Takalo H, Pettersson K. (2009) Improved surface stability and biotin binding properties of streptavidin coating on polystyrene. Colloids Surf B Biointerfaces. 70:271-7.